p-Toluenesulfonic acid → Undec-2-yn-1-ol

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Reaction Steps

To a solution of tetrahydro-2-(2-undecynyloxy)-2H-pyran in methanol (100 mL), was added p-toluenesulfonic acid (30 mg). The mixture was stirred at room temperature for 4 hours. The solvent was removed by rotary evaporation. The residue was taken up in ether (150 mL) and washed with aqueous saturated NaHCO3 (120 mL), saturated NaCl (120 mL) and water (200 mL). The organic layer was dried (MgSO4) and concentrated to yield a yellow oil. Purification by flash silica gel chromatography (90:10 hexane/EtOAc) afforded 2-undecyn-1-ol (48) (2.6 g, 77% overall) as a colorless oil: Rf 0.27 (90:10 hexane/EtOAc); IR (neat) 3300, 2925, 2855, 1437, 1110 Cm-1 ; 1H NMR (CDCl3) δ 4.18 (t, J=2.4 Hz, 2 H), 2.8 (s, 1 H), 2.14 (tt, J1 =7.2 Hz, J2 =2.4 Hz, 2 H), 1.35 (m, 12 H), 0.82 (t, J=6.9 Hz, 3 H); 13C NMR (CDCl3) δ 86.15, 78.28, 50.93, 31.76, 29.09, 29.04, 28.82, 28.56, 22.56, 18.63, 13.95. ##STR22##

Provenance & Evidence